If as stated elsewhere:
"It is very important that the "name" ends with the correct phrase, or else the game will not work properly."

Should this example not be:
<step name="chineseEndTurnNoPU" delegate="endTurnNoPU" player="Chinese">

Could a developer confirm that the name must be formatted as stated?
I wonder why that would be when you have the delegate attribute in the step.

EDIT:
Found another: The step name '...AirborneCombatMove' does not match the delegate name 'specialCombatMove'
This leads me to believe that the step name may not be used in the engine, the delegate name is the important attribute.

"It is very important that the "name" ends with the correct phrase, or else the game will not work properly."
Seems to be true, the prefix can be anything as long as each occurrence of that step type is unique (so empire names are a good option)

Safest way is to just add prefixes to POS2 step names, since we know some have hardcoded requirements for step names.

But custom step names will function if you know exactly what needs to be added/removed in form of step properties.

Also some of the xml coding and notes are simply inconsistent, thus why I mentioned previously, copying all POS2 data and adding new notes, rather than replacing POS2 notes, would both assure nothing important lost to rewrites and less work for you. Although it would be contrary to being concise.